In general, a fuel cell has a poor starting property as compared with another power source. A power generation efficiency of such a fuel cell decreases owing to lowering of a temperature and a poisoned electrode catalyst, and a desired voltage/current cannot be supplied, so that an apparatus cannot be started sometimes.
In view of such a situation, a method is suggested in which at least one of an anode fuel (e.g., a fuel gas) and a cathode fuel (e.g., an oxidizing gas) to be supplied to electrodes is brought into a shortage state, and an overvoltage of a part of the electrodes is increased to raise a temperature of the fuel cell, whereby the poisoned electrode catalyst is recovered and the fuel cell is warmed up (e.g., see Patent Document 1).    [Patent Document 1] Japanese Patent Publication No. 2003-504807